Paul addresses the person who judges others and tells him that, in condemning what he himself does, he condemns himself. God's judgment is according to the truth. Whoever thinks he will escape judgment despises the kindness, forbearance and patience of God, which are meant to lead him to repentance.
The apostle explains that God will repay each person according to their works: eternal life for those who persevere in doing good and seek glory and honor, and wrath for those who reject the truth and follow unrighteousness. This applies to the Jew first and also to the Greek, because God shows no partiality.
Those who sinned without the law will be judged without it, and those who sinned under the law will be judged by it; it is not the hearers of the law who are righteous but its doers. The Gentiles, who do not have the written law, show by nature that what the law requires is written on their hearts, and their conscience bears witness. God will judge the secrets of people through Christ Jesus.
Then Paul speaks directly to the Jew who relies on the law, boasts in God and sees himself as a guide to the blind, yet dishonors God by breaking it, so that God's name is blasphemed among the Gentiles. Finally he teaches that circumcision is worth something only if the law is kept; a true Jew is one inwardly, and true circumcision is of the heart, by the Spirit and not by the letter.